gentoo-on-rpi-64bit VS crankshaft

You're probably thinking of the now unmaintained https://github.com/sakaki-/gentoo-on-rpi-64bit. He took a %dayjob% that required him to stop committing to open source projects or, possibly, just

64 bit with gentoo i think is slightly less supported; but that is just from me looking around the package archive, and what it appears to be from the wiki. Though i am in the process of taking sakaki's 64 bit image and moving it over to use the official gentoo repos, so i guess i am glutton for punishment

Last time I was looking into this, no normal 64-bit rpi distro (including alarm) supported it. There was only gentoo that somebody hacked together offering mmal interface for h/w codecs: https://github.com/sakaki-/gentoo-on-rpi-64bit

You can build a binary distro based on Gentoo, e.g. https://github.com/sakaki-/gentoo-on-rpi-64bit (sadly EOL'ed several months ago).

Anyway, from my own experience, the video decoding performance of gentoo-on-rpi-64bit was somehow nowhere close to LibreELEC, on the same hardware. Perhaps there is a lesson to be learnt there...

yes. use gentoo. specifically this version: https://github.com/sakaki-/gentoo-on-rpi-64bit

This is very encouraging—I'm doing the same thing eventually on my Surface Pro (2017 model). Right now, I've just got it on a raspberry pi 4B 8GB. It works amazingly there, but I'm using a binary-heavy overlay and dwm. Firefox works better than I expected, but I haven't bothered with sound much, so I don't watch any video or anything. Also, the image I use (I use the “lite” variant available there) comes with an easy-to-use update tool (“genup”). At the very least, I consider it a great way to get acquainted with a significant portion of the Gentoo experience.

But, according to : https://github.com/opencardev/crankshaft/wiki/Android-Auto-Wifi

It's pi focused apparently https://github.com/opencardev/crankshaft/wiki

3)The route that I ended up going was to build my own unit with a Raspberry Pi running Crankshaft to run Android Auto and a 7" touchscreen that I mounted magnetically to a phone mount that inserts in the CD player. Doesn't look OEM butif you manage cords it looks pretty clean and works well. Also cost me under $100 and I can remove it easily any time I want. I'm a little techy so it wasn't too hard - there are tons of videos out there that will walk you through the project.

How about this? https://getcrankshaft.com/

Your other option, which I actually use in my R56, is to utilize the Crankshaft project with a Raspberry Pi and a generic 7" touchscreen from Amazon. I mounted mine with a magnetic mount from the CD drive and power it through the aux power port. Mine works both with wired and wireless Android auto, with very few glitches. If you're techy at all it doesn't take long to set up.